Rebound device piston



E. W. ACKERMAN ET AL REBOUND bEvIcE PIsToN Filed Dec. v15, 192e PatentedOct. 29, 1929 Unirse srnree;

einen arent' carica* iinivns'r W. AGKERMAN AND GRIFFITH c. Nrcnonsoiv,or ivi'oivnongivricnieniv, As-

TION OF MICHIGAN REBOUND Y:I FTIGE PISTON l Application filed' December13, 1926. Serial No. 154,429.

This invention rela-testo freedom ora rel duced resistance range indashpot devices.

This invention has utility when incorpo- `ratedin rebound absorbers orshock take up 2 looking in the direction of the arrow;

Fig. 4 is an enlarged detail view, in section, of the piston showing itsdouble or ported head control as in one position of portclosure whereinthe spring is predominant; and

Fig. 5 is a view similar to Fig. 4 with the piston device structure inposition wherein the piston operating means is predominant over thespring. f

Motor vehicle body frame 1 is shown as carried by springs 2 for relativemovement as to axles 3 having wheels 4. Bolts 5 through ears 6 anchorhousing 7 in fixed relation with the vehicle frame 1. This .housing 7 isprovided with top opening 8 closed by top 9ias anchored therewith bybolts 10. Through this housing 8 extends rock shaft 11 having fixedthereon arm 12. from which'depends flexible extension 13 to fixedconnection with an axle 3. Accordingly, in the relative movement of theaxle3 as to the frame 1 there is a rocking of the shaft 11 as to thehousing 7.V v

This shaft 11 has fixed therewith piston operating means 4or arm 14coacting with flange 15 fixed with tubular section`16 extending throughcentral opening 17 in head 18` of piston having depending skirt'19operable in cylinder 20. This cylinder 20 has head 21 with central port22 therein as an intake valve normally closed by ball 23. Cage 24 withpin 25 keeps the ball 23 in'position adjacent'the port 22. This cage 24has flange'26 engaged y compression helical spring 27 maintaining thislcage 24 in position about the port 22.

The cylinder 20 adjacent the head 21 has lateral port 28 in whichistapered lstem 29 having flattened seepage portion 30, This stem 29 maybe adjusted to regulate the seepage from the cylinder 2O by threadedportion 31 having head 32V for effecting rotation as to the housing 7.Atthe' desired adjusted seepage position for; the stem 29, nut 33 maybeoperated into locking'positionbetween the housing 7 and thethreaded'portion 31. f f

The tubular portion 16 has reduced extension 34 engaged in seat 35 offlange. y36having second tubular section 37l with :integral .closure 38remotel from thel flange 36. Bolt 39 may assemble these tubularVsections '16,

Miei-ricain, A ooiaronn- 37, as a tubular `member unit with the pair offlanges 15, 36, upon opposite lsides fof 'the piston head 18 as a doublehead for this piston effective `in the respectivepositions of theseflanges 15,-36, againstthehead-18Vfor closing yports 40 throughsaidheadj18. L

The spring 27 :from the intake valve cage flange 26 tends normally tohold Athe-flange 36 against the piston head, 18 and thu's holds' theports 40 closed with the flange 15 having clearance as to the head 18and against the operating means arm 14.' As a load is applied or aconcussion transmitted to 'overcome the actionk of the spring 27, thefloating piston18, 19, has its movement resisted by liquid 41 vas-anincompressible medium in the cylinder720,

This medium 41 is 'charged into the'hous'ing 7 to-opening 42 closed byplug 43. Thepiston 18,' 19, thus is held during the initial descent ofthe-flange 15 as actuated byfthe arm 14. Accordingly, the lports, 40 areopened and there may be some flow of the liquid 41 out from the skirtedpiston .18, 19, before the flange 15 comes into-port closed position atthe ports 40 therebyfto trap the incompressible medium inthe skirt'edpiston.- From such relatively less resistance travel region or freedom.`of theopen ports 40, 'there follows a inuch greater resistance assupplementing the spring 27 by the incompressible medium 41. Thisfurther'descent rate is governed byA the seepage adjustment of the stem29, for the check'valve 23 is closed. ,Iv .v ,Y

As this incompressible medium pressure .builds up, disastrous`conculesion .upon the Y ment range unit.

housing 7 is avoided herein by incorporating a relief valve with thisrelatively freer move- To this end the bolt 39 has nut 44 thereonassembling the tubular sections 16, 37. Adjusting nut permits regulationofthe compression ;helical spring 46 acting 1upon inwardly extendingflange 47 of plunger 48 -to hold `such plunger against closed -end I38of the #tubular fmember S36, 37, 38,' Yand thus isolate lateral port 49in the member 37 from port 50 in the flange Y member 7.15. This plunger48 has shoulder 51 exposed atV all times to pressure as developed'in'the skirted piston 18, 19, so that assuch pressure builds up 'on-the'shoulder 521 'to overcome the vadjusted resistance ofah'esprng filthfisplunger '48`m`ayVbeunseatedffrom the end portion '38 toallow flowbfthe'mediu'm 4f1through'th'e rt '.49 andi-above the inwardlygextending-gnge 47Jthrou`gh this 'phin'g-er 48 ra'nd the Itubular-members=87, 16,to be discharged at port above the piston into-air chamber52,`theretolow=backlinto themedium 41 outside the cylinder 20. VAt oncethe operatingv action ofthe a'rnrlis reduced below the holdii'ngactioniof lthe spring-4.6 this plunger 48 is resented and 'therelief valve thus closed. T-hefgdevic'e may have the Vseepage there-Kafter 1continue lat the stein 28,'Aor 'if there 'be' 'reverse movementthe spring 27,`may Vcause the "piston jto 'frise lfvvith the resultantunseat- -i'ng oftheintake check valve ball 23 and the 'Sportelloclosedby ythefange 36.

There i's accordingly @provided herein .a re- 'lief valve'unitlincoriporated with .a v'relatively free center-,fin a`device*'which permits, 'by a Asimple mechanism, a .freedom 'for shock-abfsorber actionwith the positive holding lof a hydraulicresist ance.as Wider movementrange 'causes thepr'essure 2to build up. lis claimedand it isdesi'red tosecure .by Letters Patent is;

' f1. fpisto'nfand cylinder device including fa fcylindenfa 'doubleheaded ipi'ston ltherein, a

operating-means forfpos'itively acting upon li'hefother-head and'therebyshifting `the. one

heada's tothe'piston'in overcomingthe spring and thereafter shiftingsaid vpiston rwhei-'eby .differential resistance to piston operation isprovided.

Y e. Anpiswn and cylinder fee-vice including vided.

3. A piston and cylinder device including afcylin'den a piston thereforhaving -a port and arelativilys'hitftable he'ad,5a springlnormallyholding the head in piston port closed position, and piston operatingmeans for acting against the resistance of said spring for effectingrelative movement between the piston and head for opening said port.

.4, A piston and cylinder device including a cylinder, a piston thereforhaving a port and -a Arelatively shiftable. head having two means forclosing said port, ma springnormallyholding the head in piston portclosed position in one direction,and piston operatv-ingpmeans for actingagainst the resistance the remaining portion. Y

6. A dash-pot device having" a piston,

spring providing a spring resistance range, an additional hydraulicresistance grange, valve means rendering a'portion of thefspring`resistance range free from hydraulic cooperation and imposing hydrauliccooperation upon theremaining portion, anda relief valve for thehydraulic cooperation range. i

l7; A .dash-potdevice having a pistonwith a. guide openingtherethroughandaport ad- .jacent said opening, .a lirstftubular section having aflange for closing said porton one sideya second tubular sectionIhavingalspring 'whichclosessaid port on'tlie other side, a'b-olt y.forassembling said sections into a tubular fmember, each `of ysaid sectionshaving a port, a Aspring on the bolt, `and aplunger urged by thespringt'ocutolf communication between said iports. r

8. Afdash-pot device embodying a piston, :at-spring providing a springresistance lrange therefor, aihydraulic resistance, Vand a by- '.passfor the hydraulic resistance carried by V 'said piston operable for aportion ofthe springresistance range.

9. A `piston and cylinder device including afcylinder'for aliquid, a.piston :therefor having a head anda skirt rigid therewith and throughVsaid head, 'there being ledge means les )depending therefrom,thereibeing a port s within said-skirt to provide a compressible`fmediumichamber -Ladjacent Athe under side of Asaid head, and vacompression spring 7in thek cylinder 'acting 'on said ledge.

[nfw1ti1e'ssv whereof wie affix our signatures.

ERNESTW. ACKERMAN. GRIFFITH o. NICHOLSON;

CERTIFICATE 0F coRREoTIoN.

Patent No. 1,733,851. Granted October 29, 1929, to

ERNEST W. ACKERMAN ET AL.l

it is hereby certified that error appears in the printed specificationof the abeve numrered patent requiring correction as follows: Page 2,line 96, claim 6, strike out the word "va1ve"; and ythat the saidLetters Patent should be read with this correction therein that the samemay conform to therecord of the case in the Patent Uifice.

Signed and sealed this 3rd day of December, A. D. 1929.

M. J. Moore, (Seal) Acting Commissioner of Patents.

